How do I validate a time in Rails? Limiting a user to post once a day

Question

I\'m trying to limit user\'s posts to once a day, I was thinking about checking if Time.now - last_post_time is < (second in a day) but then that would force a 24hour per

Answer 1

post = @user.posts.find(:first, :conditions => ["DATE(created_at) = DATE(?)", Time.now])
if post
  # he made a post today!
else 
  #he can post
end

So all in all, it produces this SQL query:

 SELECT `posts`.* FROM `posts` WHERE (`posts`.user_id = 1) AND (DATE(created_at) = DATE('2011-03-29 04:35:45')) LIMIT 1

Answer 2

I would probably add this check in a validation in the Post model. Perhaps something like this:

class Post < ActiveRecord::Base
  ...

  validate :date_scope

private
  def date_scope
    if Post.where("user_id = ? AND DATE(created_at) = DATE(?)", self.user_id, Time.now).all.any?
      errors.add(:user_id, "Can only post once a day")
    end
  end
end